1. Technical Field
The present invention relates generally to character recognition systems, and more specifically relates to an edge smoothing filter for correcting defects in black white image details.
2. Related Art
The ability to read and interpret character information remains an important challenge for enterprises, such as banks, that must process printed documents. In a typical application, documents such as bank checks are scanned and then character information, such as account numbers, etc., is extracted and stored. Often, during the scanning process, defects are introduced that lead to errors in the character recognition process.
One cause for such defects results from the bitonal conversion algorithms used to generate black white images. In most scanners, black white images are generated from gray scale images. A bitonal conversion algorithm is used to convert the gray scale image to a black white image, which is then read by a character recognition system, such as OCR (Optical Character Recognition), MICR (Magnetic Ink Character Recognition), thermal imaging, etc.
FIG. 1 depicts a black white image with character data (i.e., string “6 6”) containing two types of defects that are commonly introduced. As can be seen, various edges of the characters have protrusions 12 (i.e., black pixels protruding out) and/or indentations 14 (i.e., black pixels missing). More often than not, several such defects are present in character data found in black white images. These types of defects can create problems for character recognition, image scaling, etc. Accordingly, a need exists for a system and method for eliminating character defects in black white images.